Stacey Waring did a PhD on the effect of breathable roof membranes which showed just how dangerous they are to bats. She had crowdfunded future research https://www.bedsbatgroup.org.uk/wordpress/?p=9659 In this months Update Natural England have confirmed they will not authorise the use of modern roofing membranes in known bat roosts
Not only that but English Heritage are also adopting the same policy
Well done to Stacey